Differential pressure valve



June 3, 1941. w. ATCHISON DIFFERENTIAL PRESSURE VALVE Filed Jan. 50, .1940

Inventor-z Leonard W Atchison His Attorn ey Patented lune 3, 1%41 DIFFERENTIAL PRESSURE VALVE- Leonard W.- Atchison, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York 7 Claims.

My invention relates to refrigerating apparatus and more particularly to refrigerating apparatus including a plurality of evaporators adapted for operation at diiferent temperatures.

. It is an object of my invention to provide a new and improved arrangement which is -simple in structure and reliable in operation for obtaining a temperature differential between a plurality of refrigerant evaporators.

A further object of my invention is to provide a new and improved apparatus for controlling the operation of refrigerating apparatus of the above type according to the pressures existing therein.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed ting along the axis of valve l5, that is acting in a direction to close the valve l5. The valve deaforementioned component of weight. In both out with particularity in the claims annexed to the principles of my inventionas applied to a two-temperature refrigerating system utilizing parallel evaporators.

In the illustrative system disclosed in Fig. 1, I have illustrated a series refrigerating system having a high temperature evaporator III, a low temperature evaporator II and a. refrigerant liquefyiug unit including a compressor l2 and condenser [3. In a refrigerating system including high and low temperature evaporators'with a common compressor and condenser it is necessary to provide means for maintaining a pressure differential between evaporators. For this purpose I provide a differential valve device I 4 between the evaporators Ill and II. As illustrated in Fig. 2, the valve proper I5 is weighted as by means of a weight 16. Inspection of Fi s permit refrigerant to be conducted to the low temperature evaporator II when the force due to the pressure in high temperature evaporator I I becomes high enough to overbalance the combined forces due to the pressure on valve l5 caused by the pressurein the low temperature evaporator I l and the component of weight actsystems, the aforementioned pressures acting to close the valve l5 are substantially the same as the pressures in the low temperature evaporators II and II respectively.

Describing the system'shown in Fig. 1 in greater detail, I have provided a compressor l2 for compressing refrigerant vapor. The compressor l2 preferably embodies a motor-driven compressor unit which may be of the type in which a compressor and motor are directly connected and enclosed within a hermetically sealed casing. Inasmuch as compressor units are well known in the art, complete illustration thereof'is believed unnecessary. The compressor I2 withdraws evaporated refrigerant from the low temperature evaporator ll through a suction conduit l1, compresses the gaseous refrigerant and delivers it to the condenser l3 through a conduit l8. Liquefied refrigerant flowsfrom condenser l3 into a liquid receiver or float valve chamber I9 by way of a conduit 20. A low temperature 1and2willshow'thatthevalve I5willopento' evaporator I0 is supplied with refrigerant from the device 19 by way of a conduit 2|, the refrigerant which passes therethrough being controlled by an expansion valve 22 of any suitable ypa- Refrigerant is delivered to the low temperature evaporator H through conduits 23 and 24 and variable differential valve device l4.

Evaporators Ill and II may be of any desired form and may be operated at any two desired temperatures. For example, one may be maintained below the freezing temperature in order to freeze ice, desserts, etc., and also to maintain articles in a frozen state while the other evaporator may be used'for the preservation of foods at temperatures .above freezing.

In order to maintain a predetermined temperature differential between the evaporator or cooling element l0 and the evaporator or cooling element II, I have provided a pressure respormive differential .pressure valve device It. As shown in Fig. 2, the differential pressure responslve valve device l4 includes a valve proper I5 arranged within an adjustably positioned casing 25. The casing 25 is provided with a boss 26 having a passage 21 therethrough for communication with the inlet conduit 23. The boss 25 and casing 25 cooperate to form a valve seat 28 for the valve l5. In the illustrated form of my invention, the valve I5 is formed at one end of a valve rod 29, the valve rod 29 being pivotally secured to an arm 30 intermediate the ends thereof. One end of the arm 30 is pivotally connected to a stud or car 3| by means of a suitable fastening device 32, the stud 3| bein suitably'secured to or integral with a wall of the casing 25. In order to weight the valve I5 I have provided a weight member l5 suitably secured to the other end of arm 30. Casing 25 is Provided with an outlet in the form of a boss 33 having a passage 34 therethrough for communication with outlet conduit 24. The conduits 23 and 24' may be secured to the bosses 25 and 33, respectively, in any suitable manner, as by welding, for example.

In order to vary the point of operation of the valve IS, the valve casing 25 is provided with an ear or trunnion 35 having an opening 35 therein so that the casing 25 may berpivotally connected to a suitable supporting structure in any suitable manner as by a bolt and nut for example, indicated by the numeral 31.

The operation of the system will be described in connection with Fig.2. As refrigerant is evaporated in cooling element III, the pressure there- -in will increase thereby tending to open the valve l5 by lifting the valve oif its seat 28. Opposing this pressure and acting to close the valve I5 is the pressure existing in the low temperature evaporator II and the component of weight acting along the axis of valve rod 29.- When the pressure in evaporator It becomes greater than the total of the pressure in evaporator II and the above-mentioned component of weight, the valve IE will be lifted from its seat and reirigerant can then flow from evaporator ll into evaporator ll. As soon as the difference in pressure between evaporators II and II decreases to the point where the force due to the pressure inevaporator II is less than the combined forces due to the pressure in evaporator II and the aforementioned component of weight, the valve l5 again be seated cutting off communication between evaporators II and II. It will bi seenthatifthecasingfiisarrangedsothattho which the valve rod 25 is horizontal, there will be practically no component of weight tending to close the valve I5 and under this latter condiflonno diiferential of pressure will be maintained. "Thus, in order to vary the temperature differential between evaporators II and II it is ioniytoloosenthe fasteningmeans 31,

move the cas'ng 25 to a position corresponding to diilerential of temperatures and again secure the fastening means 31' to hold the casing in the desired position. Other methods ofvlrying theposition ofthevalve device II will occur to those skilled in the art. For example,.

s; that the difierential can be varied accordin toloadrequirements- If desired, reference indicia may be provided to indicate various degrees of difference in temperature.

As shown in Fig. 1, the conduits 23 and 24 have been provided with coiled portions 39 and 40, respectively, in order to provide a sufllcient degree of flexibility in conduits 23 an 24 to permit pivotal movement of the casing 25. With differences of temperature commonly prevailing in two temperature installations, suflicient flexibility will be obtained by coiling the conventional copper tubing connections although any suitable material may be employed for the conduits 23 and 24.

In Fig. 3, I have illustrated a modification of the weighted valve illustrated in Figs. 1 and 2, corresponding parts being numbered with the same numerals used in Figs. 1 and 2. In this modification, instead of providing a pivoted weight I6, a piston type weight l5 in the form of a reciprocable cylinder has been illustrated. However, the operation of the device is the same as that previously described. In order to equalize the pressure on'th'e ends -of piston l5, suitable communication therebetween is provided, as

a passage 45.

In Fig. 4, I have illustrated a modification of my invention, corresponding parts being numbered with the same numerals used in Fig. In this modification instead of illustrating a series refrigerating system I have illustrated a system in which high temperature evaporator II and low temperature evaporator H are arranged in a parallel relationship.- Liquid refrigerant is supplied to the evaporator ll through liquid line 2|, branch liquid line 4| and expansion valve 42 of any desired type. The outlet end of the evaporator II is connected to the suction line H by means of a conduit 43. The evaporator I0 is connected to 'the liquid line 2| by means of a conduit 44, the flow of a refrigerant therethrough being controlled by a suitable expansion valve 22. The outlet end of the evaporator II is connected to the suction line I! and conduit 43 by means of conduits 23', 24' and valve device l4.

The operation of the system shown in Fig. 4 is as follows: Refrigerant is furnished the low temperature evaporator II' from liquid line 2i and conduit 44 in accordance with the operation of expansion valve 42. Refrigerant will be furnished the high temperature evaporator II when expansion valve 22 and valve l5 in the valve device l4 are open. From what has been said it will be seen that valve 15 will open when the pressure at the valve end of conduit 23' is equal to the combined forces due to the pressure at the valve end of conduit 24' and the component of weight acting to close the valve I 5. Inspection of Fig. 4 shows that these pressures will be substantially equal to the pressures prevailing in evaporators II and II respectively.

While I have shown a particular embodiment of my invention, I do not desire my invention to be limited to the particular construction shown and described and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a refrigerating apparatus including a plurality of refrigerant evaporators, diiferential pressure flow controlling means associated with said evaporators for controlling the flow of refrigerant from one of said evaporators, said refrigerant evaporatorand a'second refrigerant means including a weighted valve, said valve beevaporator, differential pressure valve means being adjustably positioned whereby the component of weight of said valve tending to keep the valve in a fiow preventing position may be varied.

2. In a refrigerating system comprising a first refrigerant evaporator and'a second refrigerant evaporator, a weighted valve operating to permit the flow of refrigerant from said first evaporator when the force due to the pressure in said first evaporator and acting to open said valve is greater than the combined forces due to the pressure in said second evaporator and that component of weight of said valve acting in a direction to close said valve, said valve being adjustably positioned whereby the component of weight of said valve tending to keep the valve in a fiow preventing position may be varied.

tween said evaporators for controlling the flow of refrigerant from said first to said second evaporator, said means including a pivotally support-' ed valve casing and a'weighted valve within said casing. i i

6. In refrigerating apparatus comprising a first refrigerant evaporator and a second refrigerant evaporator, differential pressure valve means between said evapora'tors for controlling the flow of refrigerant from said first to said second evaporator, said means including a plvotally supported valve casing and aweighted valve within said 3. In refrigerating apparatus comprising a first refrigerant evaporator and a second refrigerant evaporator, a weighted valve operating topermit the flow of, refrigerant from said first evaporator when the force due to the pressure in said first evaporator and acting to open said valve is greater than the combined forces due to the pressure in said second evaporator and that component of weight of said valve acting in a direction to close said valve, said valve being adjustably positioned whereby the component of weight of said valve tending to keep the valve in a flow preventing position may be varied.

4. In refrigerating apparatus comprising a first refrigerant evaporator and a second refrigerant evaporator, a weighted valve operatingto permit the flow of refrigerant from saidfifst to I said second evaporatorwhen the force due to the pressure in said first evaporator is greater than the combined forces due to the pressure in said second evaporator and that component of weight of said valve acting in a direction to close said valve, said valve being adjustably positioned whereby the component of'weight of said valve tending to keep thevaive in a flow preventing position may be varied.

5. In refrigerating apparatus comprising a casing, said differential pressure valve means'opcrating to permit fiow of refrigerant therethrough when the force due to the pressure in said first evaporator is greater than the combined forces due to the pressure in said second evaporator and the component of weight of said valve acting in a direction to close said valve.

7. In a refrigerating system having a first refrigerant evaporator and a second refrigerant evaporator disposed in parallel relationship, each of said evaporators having a refrigerant outlet, means including a refrigerant liquefying unit-for "supplying liquid refrigerant to said evaporators and conduits connecting the outlets of said evaporators to said liqueiying unit, control means in the outlet of said first evaporator for controlling the fiow of refrigerant therethrough, said means including a valve casing having a weighted valve therein, said casing being movable for varying the component of weight of said valve acting to close said valve, said means operating to permit the flow of refrigerant through said first evaporator when theforce due to the pressure prevailing at the outlet of said first evaporator is greater than the combined forcesdue to the pressure prevailing at the outlet of said second evaporator and the component of weight of said valve acting in a direction to close said valve. v

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